logisticinv.c

/* cdf/logisticinv.c * * Copyright (C) 2003, 2007 Brian Gough * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */#include <config.h>#include <math.h>#include <gsl/gsl_math.h>#include <gsl/gsl_cdf.h>double
gsl_cdf_logistic_Pinv (constdouble P, constdouble a)
{
double x;
if (P == 1.0)
{
return GSL_POSINF;
}
elseif (P == 0.0)
{
return GSL_NEGINF;
}
x = a * log(P/(1-P));
return x;
}
double
gsl_cdf_logistic_Qinv (constdouble Q, constdouble a)
{
double x;
if (Q == 0.0)
{
return GSL_POSINF;
}
elseif (Q == 1.0)
{
return GSL_NEGINF;
}
x = a * log((1-Q)/Q);
return x;
}